1. Field of the Invention
The present invention relates generally to a signaling method for facilitating channel switching in a Wireless Local Area Network (WLAN). More particularly, the present invention relates to a signaling method and system for indicating and selecting a channel suitable for a data transmission whereby the suitable channel is indicated by means of a channel index embedded in the existing duration field.
2. Description of the Related Art
Multi-channel Media Access Control (MAC) can increase throughput through simultaneous transmission on orthogonal channels. To facilitate full utilization of the available channels, switching capability is required. Compatibility with existing Stations (STAs) is not ensured if channel switching is carried out using new control frames. This is because these new control frames, which are not known to the existing WLAN nodes, may result in the Network Allocation Vector (NAV) not being updated by the existing nodes causing a malfunction and/or require a hardware modification for implementing the multi-channel function.
Request-To-Send (RTS) and Clear-To-Send (CTS) frames are defined in an Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN. As control frames are handled in real time, these types of control frames can be used as a mean to achieve immediate channel switching. However, there is no room left for signaling a destination channel in the format of the control frame specified in the IEEE 802.11 WLAN standard.
As described above, if an RTS frame or a CTS frame is configured to indicate a data transmission channel in a WLAN capable of supporting multiple channels, network efficiency can be increased and immediate channel switching can be provided. Furthermore, and more importantly the existing STAs can still recognize the indicated data transmission channel without necessarily requiring significant hardware modification.
Accordingly, there is a need for an improved system and method for providing a signaling for channel switching, wherein the channel index, indicating which destination to switch to, can be embedded in the duration fields of RTS and CTS frames.